The trouble is BMW no longer makes that engine, so Alpina has got hold of the tooling for it and is now making it themselves. In tuning circles, this is called going the extra mile.

So why do they bother?

Because they're German and believe that if a job's worth doing, it's worth doing right. Alpina's engineers thought the twin turbo set-up better suited the needs of the B3, giving better low rev response and pick-up, and maintaining power better across the rev range. Nor is that the only change. The intercooler is 40 per cent bigger, the exhaust is by Akrapovic and saves 7.5kg, there's a new fuel pump, spark plugs, wiring loom and ECU. These are far reaching mods and they've had the desired effect. 410bhp and a fearsome 442lb ft at 3000rpm.

And while the turbocharged motor might not have the sparkling response of the M3's naturally aspirated V8, it makes up for it with a massively forceful mid-range that's more useful and exploitable in everyday driving. It's a perfectly tractable, well mannered and smooth engine

The Alpina B3 does indeed sport a twin-turbo engine - the older 3.0-litre straight six that used to underpin the 335i until BMW decided it could do the job with a single turbo (which they call, somewhat mischievously, the Twinpower turbo). The trouble is BMW no longer makes that engine, so Alpina has got hold of the tooling for it and is now making it themselves. In tuning circles, this is called going the extra mile.

I've been a bit skeptical of this claim since it was first published.

First of all he asserts that the older engine - the N54 is the only one he could be referring to based on his words - is no longer in production which we all know is flat out wrong. It is still in use in the Z4 35i and 35is.

Secondly, with Valvetronic, the B3 engine is no more an N54 than an S55 is, which is to say not an N54 at all really. If you remove everything bolted to the head, its basically an N55, no? I mean, I don't know whether they use a bone-stock N55 long-block or upgrade some of the internals such as timing assembly or cams or what have you, but why even talk about the N54 at all? In my mind they've taken an N55, removed the turbocharger and all supporting equipment, and replaced it with a twin-turbo setup.

If I recall there was some claim elsewhere about them using an N54 block casting, but it's not clear why that would even be necessary, and even less clear that it would effect the character of the engine anyway. And for that matter, it's not even clear what the difference is between an N54 and N55 block to begin with - or indeed if there is any difference at all. I guess I could easily answer that last part by looking it up in one of the parts databases.

In the end, if this engine has Valvetronic (and by the way, I don't know if Alpina even states anywhere that it does, do they? Not sure TBH), then its an N55 with TT setup much like the S55 although without the new closed deck block and other reengineering BMW has done to the rest of the long-block.

That all being said, there is every reason to believe that the S55 will be as responsive if not more so than the B3's TT N55. I just don't like the wonky over-romanticized embellishment about rescuing the N54 from the trash bin or whatever.

__________________

A gen-u-ine BMW eff-eight-zero with them tandem clutches in the transmission and that dad gum sun roof on the top-a da cawr.

Never said it was surprising... But there are a lot of people on these boards that expect the S55 to have a lot of lag (and as of now, we don't know how it will feel).

My point is that when a Alpina twin turbo N55 can get that good reviews, then there is hope that BMW M has made a good job as well

I agree that the N54 ( and N55 ) has relatively little lag for a turbo car and I also think the S55 will have a lot less lag than the B3. However BMW think it needs an anti-lag system, that should tell you that it will be far from lag free and far from as responsive as for example a good N/A engine. I expect it to be like a modern BMW turbo car but with better response at track style driving no more no less.

First of all he asserts that the older engine - the N54 is the only one he could be referring to based on his words - is no longer in production which we all know is flat out wrong. It is still in use in the Z4 35i and 35is.

Secondly, with Valvetronic, the B3 engine is no more an N54 than an S55 is, which is to say not an N54 at all really. If you remove everything bolted to the head, its basically an N55, no? I mean, I don't know whether they use a bone-stock N55 long-block or upgrade some of the internals such as timing assembly or cams or what have you, but why even talk about the N54 at all? In my mind they've taken an N55, removed the turbocharger and all supporting equipment, and replaced it with a twin-turbo setup.

If I recall there was some claim elsewhere about them using an N54 block casting, but it's not clear why that would even be necessary, and even less clear that it would effect the character of the engine anyway. And for that matter, it's not even clear what the difference is between an N54 and N55 block to begin with - or indeed if there is any difference at all. I guess I could easily answer that last part by looking it up in one of the parts databases.

In the end, if this engine has Valvetronic (and by the way, I don't know if Alpina even states anywhere that it does, do they? Not sure TBH), then its an N55 with TT setup much like the S55 although without the new closed deck block and other reengineering BMW has done to the rest of the long-block.

That all being said, there is every reason to believe that the S55 will be as responsive if not more so than the B3's TT N55. I just don't like the wonky over-romanticized embellishment about rescuing the N54 from the trash bin or whatever.

Yeah, that quote is probably inaccurate at best

My interpretation is that they have the tooling to cast the exhaust manifolds.

The official thread on the Alpina B3 also states that it's a N55 with twin turbos:

Quote:

The prerequisite for these impressive values is a high-tech engine which exhibits its own unique characteristics thanks to a significant number of stand-alone features. The goal of the engineers from Buchloe was to achieve excellent responsiveness, high output across the entire rpm range and an improvement in fuel consumption. The ‘Bi-Turbo’ engine configuration arose not only out of tradition. More to the point, this type of turbocharging has the advantage of providing very good response and pick-up due to the low mass moment inertia of the turbocharger’s running gear and sufficient rate of air-flow for spontaneous power delivery.

The design and construction of the excellent BMW 3.0 litre straight-six cylinder (N55) engine serves as a starting-point for a specially cast aluminium crankcase with Bi-Turbo capable flanges. These enable the mounting of two turbochargers along with required oil and water connections and a close-coupled catalytic converter arrangement. ALPINA specific NGK spark plugs and a forged steel high-strength crankshaft guarantee long-lasting stability.

Always-on power delivery and excellent throttle response are aided by an electronically controlled bypass valve system. Specially constructed and de-throttled, i.e. flow and cross-section optimised, air intake ducts guide the air with minimal losses from the air intake via the air filter housing to the turbochargers. On the fuel side, a high-performance high-pressure fuel pump ensures the right throughput. Optimal utilisation of the output is provided by a high-capacity intercooler with flow-optimised collector boxes made from aluminium. Coolant cooler, addi- tional separate coolant and engine oil coolers as well as a high-performance 850w cooling fan ensure the thermal stability of the cooling system in all conditions.

Not sure why this is surprising. When the N54 came out WITH ITS ORIGINAL TUNING, the reviews were basically that it was incredibly hard to tell it wasn't an NA engine anywhere above 2000 rpms.

I really don't know about all that. I have three friends that each own a pre-LCI E82 135i. I've had plenty of wheel time behind an N54, and they've all had lots of time behind the wheel of my car. All four of us agree that the throttle response is nowhere near as close on the N54 as it is on a good N/A engine.